Field
The present disclosure generally relates to service discovery. More specifically, the present disclosure relates to peer-to-peer service constraint advertisement and discovery via wireless communications.
Related Art
Wireless-enabled portable devices, such as smart phones, tablet computers, notebook computers or the like, allow users to engage in a variety of activities using wireless communication. For example, a user can use a portable device to surf the Internet, participate in a video conference call, download and listen to music clips, download and view video clips, and/or exchange information (e.g., play games or exchange contact information) with other users of portable devices.
An emerging trend for such portable devices is peer-to-peer exchange between two or more portable devices without the need for wireless access points. In this regard, technologies and applications for peer-to-peer communication have been developed to allow portable devices in the vicinity of one another to engage directly in peer-to-peer information exchange and service rendering. Thus, ideally, when two or more people with portable devices capable of peer-to-peer communication are in the vicinity of one another, they would be able to engage in peer-to-peer activities using their portable devices. However, there may be situations where two portable devices capable of peer-to-peer communication are not able to engage in meaningful transactions due to, for example, one of the devices having an older version of software. Additionally, the two devices may have disjoint capabilities, e.g., one device is equipped for 5-GHz Wi-Fi while the other device is equipped for 2.4-GHz Wi-Fi, meaning that the devices may be incapable of direct wireless communication. When such devices are unable to communicate, it can result in a poor user experience.
Wi-Fi Direct is one standard developed to enable devices to engage in peer-to-peer communication. Using Wi-Fi direct, two devices in the vicinity of each other can perform device discovery and service discovery to enable the devices to determine if the devices are present and hosting a desired service (e.g., a game application, file transfer service, printer service, etc.). More specifically, using a “scan, listen, find” process in Wi-Fi Direct, each device performs a scan of a predetermined set of channels (sometimes called “social channels”) in a random order to discover beacons transmitted by established devices on the channels, and in order to send probe requests to other devices that are discoverable and listening on the channel. Upon encountering another device's beacon frame or probe response, the scanning device can use information from the frame to determine the presence or availability of the device. Each device then sends unicast generic advertisement service (GAS) frames to the other device to perform service discovery.
However, Wi-Fi Direct has its own issues and inefficiencies. Firstly, because a device is unaware of the channel (or channels) used by another device to transmit advertising frames and the schedules of the devices may not be synchronized, the random scan of the channels in the set of channels may not encounter the advertising frame from the other device until multiple passes though the set of channels have been performed by the device. Thus, a device may need to search for a relatively long time to discover another device, which can be time- and power-consuming. Secondly, in the above-described approach, service discovery is unidirectional. This means that, after going through the above-described process, a first device may learn of a second device's presence or services but the second device may still have no knowledge of the first device's presence or services. That is, the second device may still be performing the scan of the set of channels to discover the first device. Thirdly, GAS frames are unicast frames. In other words, devices exchange service information in a one-to-one manner using GAS frames. Hence, after the first device sends one or more GAS frames to the second device only the first device, but not any other device, knows of the second device's services. When a group of users with a plurality of portable devices that desire to engage in peer-to-peer exchanges, exchanges based on unicast such as GAS frames would be very time and power consuming.